Power switches are conventionally used to couple a load with a supply voltage. In recent years, “smart” power switch devices have been developed which are equipped with one or more diagnostic abilities and protection features, for example against overloads and short circuit events. For example, in such a power switch device as a power switch a MOS transistor may be used, and the switch may be opened (i.e. caused to be non-conducting between terminals of the switch) in case of overload or short circuit events. In case of a short circuit condition (for example caused by a short circuit in a load), an undervoltage may occur. Such an undervoltage condition may lead to an opening of the power switch. However, the undervoltage condition may also cause a “restart” of the power switch, where the power switch is closed again as soon as the undervoltage condition has passed. If the short circuit condition persists, this may lead to a fast toggling between opening and closing the switch, which in turn may lead to a high number of high-energy pulses through the power switch, which may deteriorate or even destroy the power switch.
Therefore, proposals have been made to delay closing of the power switch in such situations, to avoid the aforementioned fast toggling. In conventional solutions, to store information regarding an undervoltage event, a separate supply voltage had to be provided, as the undervoltage otherwise would cause memory elements like latches to lose their stored data and therefore cause the device to “forget” that there was an undervoltage event. Such an additional supply voltage requires an additional pin of a package of the power switch, which is generally undesirable as it causes additional costs.